Thermally reflective substrate coating and method for making and applying same

ABSTRACT

A film wrap coating used to coat both metallic and non-metallic profiles for architectural and/or automotive components including a PVC backing layer which is bonded and at least partially cross-linked to a polyvinyl fluoride (PVF) film layer, and a paint or pigment layer applied to the PVF layer, most preferably, the paint applied to thermally reflective latex paint. The film wrap is formed by aligning a sheet of PVF overtop of a flexible sheet of PVC. Following the alignment of the PVC and PVF sheets, a third layer of paint is then applied to the exposed surface of the PVF sheet and the three layers are heated so that the PVC and PVF sheets fuse to each other resulting in at least partial cross-linking therebetween, and the paint on the pigment layer cures and fuses to the PVF sheet.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 09/228,493, filed Jan. 11, 1999, and entitled “ThermallyReflective Substrate Wrap” now U.S. Pat. No. 6,120,886.

SCOPE OF THE INVENTION

The present invention relates to a thermally reflective substratecoating and a method for making and applying such a coating, and moreparticularly a wrap coating which may be applied to profiles such asthose used to form architectural or automotive components and which hasimproved scratch and distortion resistance.

BACKGROUND OF THE INVENTION

Various spray coatings have been proposed for use in reducing thetemperature rise associated with sun light exposure on metallic andnon-metallic substrates. One such coating is disclosed in U.S. Pat. No.4,546,045 to Elias, which issued Oct. 8, 1985, and involves theapplication of a paint composition comprised of a film forming polymerand an infrared reflective pigment to polyvinyl chloride (PVC) substrateprofile. Following the application of the coating composition, thesubstrate profile is baked at 130° F. for approximately twenty minutesto ensure proper coating adhesion to the substrate profile.

A difficulty with conventional coating techniques exists in thatdepending upon the substrate or profile to be coated, it may not beeconomically or physically possible to bake the painted PVC profile toprovide the required curing for proper adhesion of the thermallyreflective paint. In particular, often it is desirable to providecoatings to PVC profiles which are used in the formation ofarchitectural components such as pilasters, windows and doors. Suchprofiles are manufactured off site and are coated as elongated PVC orother plastic extrusions prior to final door or window assembly.Similarly, it is envisioned that various plastic profiles used in theautomotive industry to form bumpers, fenders and other auto parts may betoo large or cumbersome to heat cure and achieve the necessary adhesionof the thermally reflective paint.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to overcome atleast some of the disadvantages of the prior art by providing athermally reflective wrap coating which may be applied as a coating to anumber of different profiles made from wood, metal, or AmericanArchitectural Manufacturer's Association (AAMA) #303 certified plasticsincluding polyvinyl chloride (PVC), sheet molding compound (SMC),acrylonitrile-butadiene-styrene resins (ABS), polyphenylene oxide (PPO),nylon, polystyrene, fibreglass and any other non-metallic or syntheticsubstrates including those suitable for use as architectural and/orautomotive components.

Another object of the invention is to provide a coloured wrap coatingfor substrate profiles which includes a thermally reflective paint orpigment layer, and which may be secured to an exposed surface of theprofile by conventional processes, including cold and/or hot gluing,sonic welding, hot welding, and the like.

Another object of the invention is to provide a wrap coating fornon-metallic materials made from AAMA plastics which provides materialwith increased thermal reflectivity and ultra-violet (UV) protection, toprolong the product life.

Another object of the invention is to provide architectural orautomotive components with factory-applied organic coatings, which willprovide and maintain a superior level of performance in terms of filmintegrity, exterior weatherability and general appearance over a periodof many years.

The invention resides in an improved flexible film wrap which may beused to coat both metallic and non-metallic profiles, including wood andplastics, and which preferably include profiles used as architecturaland/or automotive components. The film wrap includes a PVC backing layeror sheet which is bonded and at least partially cross-linked to apolyvinyl fluoride (PVF) film layer, and a paint or pigment layerapplied to the PVF layer. Most preferably, the pigment layer isthermally reflective paint, as for example is disclosed in U.S. Pat. No.4,546,045 to Elias.

To form the film wrap, a first surface of a flexible 0.5 to 3 mil thicksheet of PVF is aligned overtop of a flexible 1 to 7 mil thick sheet ofPVC. Following the alignment of the PVC and PVF sheets, a third layer ofthe thermally reflective paint is then applied to the second otherexposed surface of the PVF sheet and the three layers are heated. Mostpreferably, heating occurs at between approximately 275° and 375° F. forapproximately 1 to 10 minutes until such time as the PVC and PVF sheetsfuse to each other, resulting in at least partial cross-linkingtherebetween, and the paint or the pigment layer cures and fuses to thePVF sheet.

The paint layer may be: applied to the PVF sheet in a number ofdifferent manners, as for example, by spraying, brush coating or rollcoating. Most preferably, the paint layer is applied as a layer having awet thickness of about 0.5 to 3 mil, and dries to a thickness of 0.5 to1.2 mil, and more preferably 0.8 to 1 mil.

It has been found that the wrap coating may be secured as a coveringlayer to a number of different profiles. Most advantageous, however, ithas been found that the PVC backing of the wrap coating may be securedto an exposed surface of a non-metallic profile, including those madefrom PVC, SMC, ABS, PPO, nylon, polystyrene and fiberglass, which areused to form either architectural components such as pilasters, windowand door frames, or automotive components such as bumpers, dash boards,consoles and the like. The wrap coating may be secured to the profilesin a number of conventional manners, including by cold gluing, heatwelding or fusing and sonic welding. The applicant has appreciated,however, one preferred method whereby a polyurethane reactive hot-meltglue is used to secure the PVC backing layer of the coating directly tothe profile.

Accordingly, in one aspect the present invention resides in a thermallyreflective flexible wrap for use in coating articles, comprising

a polyvinyl chloride backing layer,

a polyvinyl fluoride layer at least partially crossed linked to thebacking layer, and a pigment coating layer applied to the polyvinylfluoride layer, said pigment coating layer having a thickness selectedat between 0.5 and 2 mils.

In another aspect, the present invention resides in a method ofmanufacturing a flexible thermally reflective coating wrap comprising apolyvinyl chloride backing sheet, a polyvinyl fluoride sheet at leastpartially, crossed linked to the backing layer, and a pigment coatinglayer applied to the polyvinyl fluoride layer having a thicknessselected at between 0.5 and 2 mils, said coating wrap being formed bythe steps of,

positioning a first surface said polyvinyl fluoride sheet in overlyingjuxtaposition with a first surface said polyvinyl chloride sheet;

applying said pigment to a second other surface of said polyvinylfluoride sheet; and heating said polyvinyl chloride sheet, saidpolyvinyl fluoride sheet and said pigment at a temperature selected atbetween about 250 and 400° F. to substantially cure said pigment and atleast partially cross link polyvinyl fluoride sheet and said polyvinylchloride sheet to each other.

In a further aspect, the present invention resides in a process forcoating a substrate with a thermally reflective film coating,

said film coating comprising a polyvinyl chloride backing layer, apolyvinyl fluoride layer at least partially crossed linked to thebacking layer, and a pigment coating layer applied to the polyvinylfluoride layer having a dry thickness selected at between 0.5 and 2mils,

said substrate being coated by the steps of

applying a hot melt glue in a melted state to an exposed surface of saidsubstrate; while said hot melt glue remains in said melted statepositioning said film coating on said exposed surface.

In a further aspect, the present invention resides in a coated componentcomprising a non-metallic substrate selected from an architecturalcomponent and an automotive part component, and a thermally reflectivewrap secured to at least one exposed surface of said non-metallicsubstrate, said wrap comprising

a polyvinyl chloride backing layer,

a polyvinyl fluoride layer at least partially crossed linked to thebacking layer, and a pigment coating layer applied to the polyvinylfluoride layer, said pigment coating layer having a thickness selectedat between 0.5 and 2 mils.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects and advantages of the invention will appear from thefollowing description taken together with the accompanying drawings inwhich:

FIG. 1 shows a schematic cross-sectional enlarged view of a wrap coatedwindow sill profile in accordance with a preferred embodiment of theinvention;

FIG. 2 shows schematically a production assembly line used in the wrapcoating of the window sill profile shown in FIG. 1;

FIG. 3 shows graphically the heat absorption for films of variouscoloured PVC laminates and extrusions;

FIG. 4 shows graphically the thermal reflective properties of coated anduncoated polyvinyl chloride extrusions;

FIG. 5 illustrates schematically a preferred apparatus for manufacturinglaminated PVC and PVC layers used in the wrap coating of the presentinvention; and

FIG. 6 shows schematically an apparatus used in the application ofthermally reflective paint to form the wrap film.

DETAILED DESCRIPTION OF THE DRAWINGS

Reference is now made to FIG. 1 which shows a coated window sashcomponent 10 in accordance with the preferred embodiment of theinvention. The window sash component consists of a polyvinyl chloride(PVC) sash profile or substrate 12 which has a flexible three layer wrapcoating 14 secured to its outer exposed surface 16 by a layer of hotmelt glue 18.

The wrap coating 14 consists of an inner PVC backing layer 20, apolyvinyl fluoride (PVF) intermediate layer 22 and an outer paint layer24. The PVC backing layer is formed from a flexible PVC sheet having athickness of approximately 2 to 6 mils and more preferably 3 to 5 mils.As will be described, the backing layer 20 is cross-linked to the PVFintermediate layer 22 through partial heat melting. The PVF layer 22 mayfor example be of a flexible film type sheet such as TEDLAR™ films sold;by DuPont to provide enhanced UV blocking properties to the window sashcomponent 10. The PVF layer 22 has a thickness of between about 0.7 and2 mils, and more preferably 0.87 and 1.5 mil. For example, preferred PVFfilms would have compositional ranges as shown in Table 1.

TABLE 1 Components Material % by weight Polyvinyl Fluoride Polymer 64-86Titanium Dioxide  2-30 Calcium Carbonate  0-15 Amorphous Silica 0-5 IronOxide 0-5 Other Nonregulated Colorants (optional) 0-1 Dimethyl Acetamide(DMAC) <1 Hydrogen Fluoride <1 Nickel Antimony Titanium Yellow Pigment(optional) 0.04-25   Carbon Black (optional) <1

Decomposition temperature 204° C.

The outer paint layer 24 provides the wrap coating 14 with the desiredfinished color. Most preferably, the paint layer 24 is water based toprovide for reduced toxicity and may further be an infrared reflectivepaint such as those sold by PPG Canada Inc. under the product trade nameEnviron HR™. The paint layer 24 has a dry thickness selected at aboutbetween 0.06 and 1.4 mils, and more preferably 0.08 and 1.1 mil. It hasbeen found that improved thermally reflective properties may be achievedwhere the paint layer 24 is maintained at the preferred dry thickness.More particularly, if the paint layer 24 is too thick, the layer 24 willact as a heat sink, diminishing the thermally reflective properties ofthe coating 18.

As shown best in FIG. 5, the coating wrap layer 14 is formed by placinga first surface of the PVF sheet 22 flat against a first surface of thePVC backing sheet 20. Most preferably, the base or backing sheet 20 isin an initially semi-rigid form and is fed from an unwinder 50 through aPUR (polyurethane) coating head 52 where a polyurethane adhesive isapplied. Downstream from the coating head 52, the PVF sheet 22 such asDupont Tedlar™, is supplied from a second unwinder 54. The PVF sheet 24is corona treated and laminated to the sheet 20 by pressure rollers 58.After laminating, the fused sheets 20,22 are rewound, ready for paintcoating.

FIG. 6 shows best the apparatus 60 used in the application of the paintlayer 24 to the laminated sheets 22,20. The laminated sheets 22,20 areunwound from a supply spool (not shown) and moved via a coating roll 64into a liquid paint trough 66. The laminated sheets 22,20 are movedthrough the trough 66 so that the infrared reflecting paint 24 isapplied to the exposed surface of the PVF sheet 22. Once coated, thepaint layer 24 is preferably immediately moved past an air knife coater68, such as those sold by Magnal Machinery Inc. of Florence, Ma., U.S.A.The air knife coater 68 provides a substantially uniform angled air jetforce across the coated surface to ensure a uniform paint layerthickness. Other methods of paint application including brushing,spraying and other rolling applications are, however, also possible. Toachieve the desired dry layer thickness, paint layer 24 is most providedapplied in a wet thickness selected at between approximately 0.5 and 3mil, preferably 1.8 and 2.6 mil, and more preferably about 2.2 mil.

Following the application of the paint layer 24 to the PVF layer 22, thethree layers are heated to a temperature of be tween about 275 and 375°F. by catalytic infrared exposure, and more preferably about 325 to 330°F. for a period of between 1 and 5 minutes, until complete curing andbonding of the paint, layer 24 to the PVF layer 22 has occurred, and thePVF layer 22 bonds and achieves cross linking with the PVC backing layer20. During curing, the wrap coating 14 may optionally be cast onto aTeflon™ coated belt for final cooling.

Once cooled, the wrap coating 14 has been found to be quite stretchableand flexible with the paint layer 24 providing the desired pigmentcolour. In addition, the application of the paint layer 24 in a drythickness of at least about 0.8 mil results in the wrap coating 14 beingvisibly free from flow lines, streaks, blisters or other surfaceimperfections in the dry-film state on exposed surfaces when observe dat a distance of 10 feet (305 cm) from the coated surface and inspectedat an angle of 90 degrees to the surface.

While it is possible to Wrap almost any profile or substrate with thefilm, including those made from wood or metals, such as steel, the wrapcoating 14 is most preferably used with AAMA (#303 ) certified plasticsincluding those such as PVC, SMC, ABS, PPO, nylon, polystyrene andfibreglass.

FIG. 2 shows a preferred apparatus 26 used in wrapping the PVC windowsash profile 12 shown in FIG. 1. In use of the apparatus 26, the windowsash profile 12 would be delivered uncut, as an elongated profile 5 to20 meters in length. The uncoated profile 12 is moved via a conveyorline 28 in the direction of arrow 29. Initially the profile 12 moves onthe conveyor 28 under a glue work station 30 where the polyurethanereactive hot melt glue layer 18 is first applied to the surface 16 ofthe profile 12. Immediately following the application of hot melt glue18 and while the glue 18 remains in an uncured, melted state, the wrapcoating 14 is unrolled from a storage spool 32 and positioned as a flatsheet on the surface 16. Following the application of the wrap coating14 on the exposed surface 16, the profile 12 is moved through a seriesof pressure rollers 34 which are used to press and properly position thewrap coating 14 on the surface 16, and eliminate any air bubblestherebetween. As the hot melt glue layer 18 cools, the window sashprofile 12 is then moved through a shearing station 36 where any excesswrap 14 is trimmed and removed. Following the completion of the coatingprocess, the sash component 10 may be cut into desired lengths for finalassembly into a window frame (not shown).

FIG. 3 graphically illustrates the heat absorption properties of variouscoloured paints, concentrated European films, a s well as those of blackand white coloured polyvinyl chloride, as compared to the PVC/PVF filmof the present invention. FIG. 4 similarly represents the properties ofthermal reflectivity for PVC extrusions having either solid colours,those laminated with conventional exterior foils, and those when coveredwith a PVC/PVF wrap coating in accordance with the present invention. Asis apparent, the PVC/PVF film of the present invention advantageouslyprovides the wrapped substrate with thermally reflective propertieswhich approach that of white PVC.

Although the preferred embodiment describes the use of a hot melt gluelayer 18 to secure the wrap coating 14 to the exposed surface 16, othermeans of securing the coating 14 to the profile 12 may also be used. Forexample, if desired, the coating 14 could be secured in place by heat orsonically fusing the PVC backing layer 20 directly to the PVC profile12. Alternately, cold adhesives or, separate fusible layers could beinserted between the coating 14 and profile 12 to bond the wrap coating14 in place.

While the detailed description describes the application of the wrapcoating 14 to a PVC window sash profile 12, the invention is not solimited. If desired, the coating 14 could be used as a coating forprofiles made for various other purposes including other architecturalcomponents, automotive parts such as bumpers, consoles and dash boards,or with almost any other substrates which are currently wrapped withvinyl.

Although the detailed description describes various preferredembodiments of the invention, the invention is not so limited. Manymodifications and variations will now occur to persons skilled in theart. For a definition of the invention reference may be had to theappended claims.

We claim:
 1. A method of manufacturing a flexible thermally reflectivecoating wrap comprising a polyvinyl chloride backing sheet, a polyvinylfluoride sheet at least partially crossed linked to the backing sheet,and a pigment coating layer applied to the polyvinyl fluoride sheet,said coating wrap being formed by the steps of, securing a first surfacesaid polyvinyl fluoride sheet substantially in overlying juxtapositionwith a first surface said polyvinyl chloride sheet; applying saidpigment coating to a second other surface of said polyvinyl fluoridesheet; and heating said polyvinyl chloride sheet, said polyvinylfluoride sheet and said pigment coating at a temperature selected atbetween about 250 and 400° F. to substantially cure said pigment coatingand at least partially cross link polyvinyl fluoride sheet and saidpolyvinyl chloride sheet to each other.
 2. The method of claim 1 whereinsaid polyvinyl fluoride sheet is secured to said polyvinyl chloridesheet by pressure rolling said sheets together.
 3. The method of claim 1wherein said pigment coating comprises an infrared reflective paint. 4.The method of claim 1 wherein said pigment layer is applied by movingsaid polyvinyl fluoride layer through a reservoir liquid pigment, andthereafter passing said coated wrap through an air knife apparatus priorto said pigment curing.
 5. The method as claimed in claim 4 wherein saidheating step is performed at a temperature of between about 325° and330° F. for a period of between about 1 and 5 minutes.
 6. The method ofclaim 1 wherein said polyvinyl chloride sheet has a thickness selectedat between about 1 and 7 mil, said polyvinyl fluoride sheet has athickness selected at between about 0.5 and 3 mil, and said pigmentcoating comprises an infrared reflective paint, wherein said pigmentcoating is applied to said second surface in a wet thickness of betweenabout 0.5 and 3 mils.
 7. A process for coating a substrate with aflexible thermally reflective film coating, said film coating comprisinga polyvinyl chloride backing layer, a polyvinyl fluoride layer at leastpartially crossed linked to the backing layer, and a pigment coatinglayer applied to the polyvinyl fluoride layer having a dry thicknessselected at between 0.5 and 2 mils, said substrate being coated by thesteps of, applying an adhesive to an exposed surface of said substrate;and while said adhesive remains in an uncured state, positioning saidfilm coating on said exposed surface.
 8. The process as claimed in claim7 wherein said substrate is made of a non-metallic material selectedfrom the group consisting of polyvinyl chloride, sheet molding compound,acrylonitrile-butadiene-styrene resin, polyphenylene oxide, nylon,polystyrene and fiberglass.
 9. The process as claimed in claim 8 whereinsaid polyvinyl chloride backing layer has a thickness selected betweenabout 3 and 5 mil, said polyvinyl fluoride layer has a thicknessselected between about 0.87 and 1.5 mil, and said pigment coating layerhas a dry thickness selected between about 0.8 and 1.1 mil.
 10. Theprocess as claimed in claim 9 wherein said substrate is selected fromthe group consisting of a pilaster, a window frame component, a doorframe component, a vehicle bumper, a vehicle dash board and a vehicleconsole.
 11. The process of claim 9 wherein said pigment comprises aninfrared reflective paint.
 12. The process as claimed in claim 8 whereinsaid adhesive comprises a polyurethane reactive hot-melt glue.
 13. Theprocess as claimed in claim 12 wherein said substrate is selected fromthe group consisting of a pilaster, a window frame component, and a doorframe component.
 14. The process of claim 13 wherein said pigmentcomprises an infrared reflective paint.
 15. The process as claimed inclaim 12 wherein said substrate is selected from the group consisting ofa vehicle bumper, a vehicle dash board and a vehicle console.
 16. Theprocess of claim 15 wherein said pigment comprises an infraredreflective paint.
 17. The process as claimed in claim 7 wherein saidsubstrate is selected from the group consisting of a pilaster, a windowframe component, a door frame component, a vehicle bumper, a vehicledash board and a vehicle console.